Think about the last time you gave a presentation. The feeling of having “butterflies in your stomach”. Or when you meet someone for the first time, that “gut feeling” of whether you two will get along. In our day-to-day lives, we often associate what happens in the gut with what goes on in our brain. In fact, scientific evidence suggests that our gut and our brain frequently communicate—through gut microbes. Apparently, the existence of trillions of bacteria and eukaryotes in our gut is not only crucial for our physical health, they may also be important for our mental health.